1. Field of the Invention
The invention relates to a technique, specifically a method, an apparatus, and an article of manufacture implementing the method, to perform archiving transparently.
2. Description of the Related Art
Database management systems allow a user to access data quickly and conveniently. In database management systems, data is stored in tables. Physically, the tables are typically stored on hard disk drives so that the data may be accessed quickly.
FIG. 1 depicts an exemplary database table 10 of a database management system. The table 10 has rows 12 and columns 14 to store data. A row 12 is also referred to as a record.
Archive storage is also used to store data. Typically, the storage devices of an archive storage system are slower and less expensive than hard disk drives. As a database grows, that is, as records are added to the tables of the database, the amount of data may become too large to be conveniently managed in a single database, degrading user response time and system performance. In addition, much of this data may never need to be accessed again; however, the data needs to be preserved. Therefore, typically a portion of the data is deleted from the database and moved to archive storage.
In the financial sector, applications such as trading desks collect a large amount of data in databases. Various governmental regulations mandate that the data be retained for very long periods of time. In these applications, recent data is referenced often; older data is referenced occasionally, and perhaps never again. As the amount of data grows, the older data is archived to keep the database small and manageable, provide a better response time, and allow utilities such as backup to run faster. That archive storage typically costs less to maintain than some other types of storage, also provides an incentive for archiving.
Typically, the process of archiving, and retrieving data from archive storage, especially relational data from a relational database management system, is performed manually by a system administrator. When retrieving archived data, finding the desired archived data is often a challenge that requires manual intervention and a separate search of the archive media. Therefore, the user cannot access the combination of the archived and non-archived data in a single request, and the user is not provided with a combined presentation of the archived and non-archived (or live) data.
Therefore, there is a need for a method, apparatus and article of manufacture to allow a user to transparently both archive and access archived data. In addition, the method should also allow a user to combine both archived and non-archived (or live) data using a single query against the live data.